The rotary wing of this invention is particularly applicable to that class of rotary wing aircraft known as "tilt-rotor convertiplanes". These aircraft resemble conventional airplanes but have lifting rotors mounted at their wingtips. These lifting rotors are mounted to the wing structure through journal bearings mounted on the spanwise axis of the wing. These bearings allow the rotor shaft to be vertical for operation as a helicopter for hovering and low speed flight. However, as forward flight speed increases, the fixed wing of the aircraft develops aerodynamic lift and the rotor shafts tilt forward allowing the lifting rotors to function as propellers. For optimum performance of such a dual purpose rotor it is desired that blade root angle and blade twist be relatively small in the helicopter mode. However, as the rotor tilts forward to become a propeller, propulsive efficiency will be improved if the blade root angle is increased and blade twist is increased. The rotary wing described herein makes such a transition feasible. Thus, this variable twist rotor provides optimum blade twist for helicopter flight and automatically increases blade twist during conversion to airplane configuration to also provide optimum blade twist for propeller operation.